Glomus tumors are rare, benign, painful, blue-red soft tissue neoplasms originating from glomus bodies in the skin. They typically present in adults 20–40 years and are most commonly found in the distal extremities under the nails. Management consists of surgical excision of the lesion, which usually leads to complete resolution. Malignant glomus tumors and metastases are exceedingly rare.
- ∼ 1–5% of all soft tissue tumors of the arms
- Solitary glomus tumors: 20–40 years
Multiple glomus tumors
- More common in children
- Some are congenital
Epidemiological data refers to the US, unless otherwise specified.
- Autosomal dominant inheritance in most multiple glomus tumors
Glomus tumors are benign, hamartomatous proliferations of modified smooth muscle cells that originate from glomus bodies.
- Glomus bodies are located in the skin, mainly of the fingers and toes, and are involved in temperature regulation.
- They contain specialized arteriovenous anastomoses that shunt blood away from the skin surface in cold weather to prevent heat loss and towards the skin surface in hot weather to promote heat dissipation.
- Malignant transformation (glomangiosarcoma) is extremely rare and typically locally infiltrating.
- Small (< 2 cm), blue-red nodules or papules in the hand, foot, and under fingernails
- Severe focal paroxysmal pain, tenderness, and cold sensitivity
Solitary (common) or multiple findings (rare) 
- Multiple glomus tumors (glomangiomas or glomuvenous malformations) account for < 10% of cases
- Tumors can be distributed over the whole body and are usually asymptomatic.
- Glomus tumors are diagnosed clinically.
- Imaging procedures assess the size and exact location, while findings of glomus cells in the excised tumor confirm the diagnosis. 
- Uniformly round, small glomus cells
- Pale eosinophilic cytoplasm associated with vasculature
- Plain radiography: bony erosions in subungual lesions
- Determines exact size and location of tumor
- Shows a hypoechoic nodule with prominent vascularity
The differential diagnoses listed here are not exhaustive.
- Total surgical excision of the lesion
- Recurrence is rare.
Classification of the various types of glomus tumors
- Carotid body
- Paraganglioma of the middle ear
- Peripheral glomus tumors (intravascular papillary endothelial hyperplasia; Masson tumor): originate from arteriovenous anastomoses
- Multiple glomus tumors: autosomal‑dominant inheritance with multiple glomus tumors in the skin and internal organs